feat: initial Lam Agent extension (#1)

src/__tests__/utils.test.ts

@@ -0,0 +1,65 @@
+import { describe, expect, it } from "vitest";
+import { errorMessage, formatRelativeTime, titleFromPrompt, truncate } from "../lib/utils";
+
+describe("truncate", () => {
+  it("collapses whitespace so list rows never wrap unexpectedly", () => {
+    expect(truncate("hello\n\n   world", 40)).toBe("hello world");
+  });
+
+  it("leaves short text alone", () => {
+    expect(truncate("short", 40)).toBe("short");
+  });
+
+  it("clips with an ellipsis at the requested width", () => {
+    const result = truncate("a".repeat(100), 10);
+    expect(result).toBe(`${"a".repeat(9)}…`);
+    expect(result).toHaveLength(10);
+  });
+});
+
+describe("formatRelativeTime", () => {
+  const now = 1_700_000_000_000;
+
+  it("reports very recent timestamps as just now", () => {
+    expect(formatRelativeTime(now - 5_000, now)).toBe("just now");
+  });
+
+  it("reports minutes and hours", () => {
+    expect(formatRelativeTime(now - 12 * 60_000, now)).toBe("12m ago");
+    expect(formatRelativeTime(now - 3 * 3_600_000, now)).toBe("3h ago");
+  });
+
+  it("reports days within the last week", () => {
+    expect(formatRelativeTime(now - 2 * 86_400_000, now)).toBe("2d ago");
+  });
+
+  it("treats clock skew as just now rather than a negative age", () => {
+    expect(formatRelativeTime(now + 60_000, now)).toBe("just now");
+  });
+});
+
+describe("titleFromPrompt", () => {
+  it("uses the first non-empty line, stripped of markdown decoration", () => {
+    expect(titleFromPrompt("\n\n## How do I deploy?\nmore text", 60)).toBe("How do I deploy?");
+  });
+
+  it("falls back to a placeholder for an empty prompt", () => {
+    expect(titleFromPrompt("   \n  ", 60)).toBe("New chat");
+  });
+});
+
+describe("errorMessage", () => {
+  it("unwraps Error instances", () => {
+    expect(errorMessage(new Error("boom"))).toBe("boom");
+  });
+
+  it("passes strings through", () => {
+    expect(errorMessage("plain failure")).toBe("plain failure");
+  });
+
+  it("survives values that cannot be serialised", () => {
+    const circular: Record<string, unknown> = {};
+    circular.self = circular;
+    expect(typeof errorMessage(circular)).toBe("string");
+  });
+});